Chemokine receptor 5 (CCR5) deletion polymorphism in North Indian patients with coronary artery disease

Background Polymorphisms in genes coding for chemokine receptors, CCR2 and CCR5 have been studied as genetic markers of coronary artery disease (CAD). V64Ile polymorphism in CCR2 has been implicated in the manifestation of myocardial infarction in different populations, but data on association of the CCR5 deletion variant in etiology of CAD are conflicting. In the present study we tested genetic association between CCR5 Δ32 polymorphism and CAD among North Indians (Uttar Pradesh). Methods Two hundred angiographically proven patients with coronary artery disease and two hundred age, sex and ethnically matched controls were genotyped for CCR5 Δ32 polymorphism by polymerase chain reaction. Genotype/allele frequencies were compared in patients and controls using the chi-square test. Results The frequency of the heterozygote genotype in the population, including both patient and control group, was 3% and the frequency of the mutant allele Δ32 was 1.5%. CAD patients had a three times higher (4.6% vs. 1.5%) frequency of heterozygote genotype but the differences were statistically not significant. Association analysis did not achieve statistical significance, though odds ratio of 3.13 was observed for heterozygote genotype. Conclusions The allele frequency of the CCR5 Δ32 polymorphism in CAD patients is 2.25% and 0.75% among controls but the differences were not significant. Overall this fits well with the pattern of CCR5 Δ32 allele frequency in Indian subcontinent where it varies from 1 to 3%. The heterozygote (+/ Δ32) genotype does not seem to have any protective role against development of CAD in this population. In fact, North Indian CAD had a higher frequency of CCR5 Δ32 allele suggesting a possible susceptibility trend (odds ratio 3.08, CI 0.83–11.46, chi-square 2.167, NS).